corona-stats.el

;; Package-Requires: ((request "0.3.2"))
(require 'request)

(defmacro access (trail value)
  (let ((trail_ (reverse trail))
        (result value))
    (dolist (focus trail_ result)
      (pcase focus
        (`(vector . ,index) (setq result `(aref ,result ',index)))
        (`(object . ,key) (setq result `(alist-get ',key ,result)))))))

(defmacro vector-alist-let (spec value body)
  (let ((varlist '())
        (stack `((,spec . nil))))
    (while stack
      (let* ((_ (pop stack))
            (focus (car _))
            (trail (cdr _)))
        (cond
         ((listp focus)
          (dolist (spec focus)
            (pcase spec
             (`(,key . ,spec)
              (push `(,spec . ((object . ,key) . ,trail)) stack))
             (`,key
              (push `(,key . ((object . ,key) . ,trail)) stack)))))
         ((vectorp focus)
          (let ((index 0))
            (mapc (lambda (elt)
                    (push `(,elt . ((vector . ,index) . ,trail)) stack)
                    (setq index (1+ index)))
                  focus)))
         ((symbolp focus)
          (push `(,focus (access ,trail ,value)) varlist)))))
    `(let ,varlist ,body)))

(request
  "https://corona-stats.online/PH?format=json"
  :params '(("key" . "value") ("key2" . "value2"))
  :parser 'json-read
  :success (cl-function
            (lambda (&key data &allow-other-keys)
              (vector-alist-let
               ((data . [(cases todayCases deaths todayDeaths)]))
               data
               (setq corona-stats (format " [COVID-19 %d(^%d) dead: %d(^%d)]" cases todayCases deaths todayDeaths))))))

(add-to-list 'global-mode-string 'corona-stats 'APPEND)